Efeitos hemodinâmicos imediatos da infusäo rápida de soluçäo hipertônica de cloreto de sódio-dextran-70 para tratamento de choque hemorrágico em cäes / Early Hemodynamic Effects of the Rapid Infusion of NaCl/Dextran Hypertonic Solution as Treatment for Hemorrhagic Shock in Dogs

RESUMO

PURPOSE--To study the early hemodynamic effects of the rapid infusion of 7.5g/dl NaCl/ 6g/dl dextran-70 solution in dogs submitted to hemorrhagic shock. METHODS--Mongrel dogs were anesthetized with pentobarbital and a electromagnetic flowmeter probe was placed around the ascending aorta or the portal vein. By external bleeding the arterial pressure was lowered to 40mmHg and held for 30min. The animals received a 4ml/kg infusion of the hypertonic solution in 90s. Arterial blood pressure and flow were registered continuously during 3min and the derived hemodynamic variables were calculated at regular time intervals. RESULTS--The total plasma protein concentration decreased and the cardiac output showed a continuous elevation during the infusion. The arterial blood pressure showed two oscillations and then decreased during a short period of time. This moment was coincident with the initial increase of the portal flow and preceded the elevation of the systemic vascular resistance and the arterial pressure. CONCLUSION--The rapid infusion of hypertonic NaCl/dextran solution to dogs in hemorrhagic shock determines immediate and intense hemodynamic effects. During the infusion period there is volemic expansion and the cardiac output increases rapidly. The arterial pressure shows oscillations and decreases as a consequence of visceral arterial dilation before starting its final elevation that occurs as the vascular resistance increases

ABSTRACT

Purpose - To study the early hemodynamic effects of the rapid infusion of 7.5g/dl NaCl/ 6g/dl dextran-70 solution in dogs submitted to hemorrhagic shock. Methods - Mongrel dogs wore anesthetized with pentobarbital and a electromagnetic flowmeter probe was placed around the ascending aorta or the portal vein. By external bleading the arterial pressure was lowered to 40mmHg and held for 30min. The animals received a 4ml/kg infusion of the hypertonic solution in 90s. Arterial blood pressure and flow were registered continuously during 3min and the derived hemodynamic variables were calculated at regular time intervals. Results - The total plasma protein concentration decreased and the cardiac output showed a continuous elevation during the infusion. The arterial blood pressure showed two oscillations and then decreased during a short period of time. This moment was coincident with the initial increase of the portal flow and preceded the elevation of the systemic vascular resistance and the arterial pressure. Conclusion - The rapid infusion of hypertonic NaCl/dextran solution to dogs in hemorrhagic shock determines immediate and intense hemodynamic effects. During the infusion period there is volemic expansion and the cardiac output increases rapidly. The arterial pressure shows oscillations and decreases as a consequence of visceral arterial dilation before starting its final elevation that occurs as the vascular resistance increases